Reporter: Brittany deen just gave birth to the heaviest triplets in the world. Meet sidney, elliott, and little brother, jenson. Combined, the threesome is 20 pounds. A big delivery for the sacramento couple, who originally planned on a small family. Oh, wow. Oh, wow. Reporter: They conceived the triplets naturally. That happens about 1 in 8,000 pregnancies. Brittany was determined to carries the babies as long as she could. And started a blog to document her growing belly. Brittany tripled the amount of food she ate, bringing in 6,000 calories some days. Eating full meals every two hours. I was just supposed to eat. Reporter: She posted this picture of what she ate for breakfast. Three eggs, yogurt, cheese slices and a bagel loaded with butter. One morning, she had made a plate of meatballs. Reporter: Brittany gained 85 pounds. But eating so many calories could have caused major problems. High blood pressure, diabetes at pregnancy. It's a risk for the mom. Reporter: Defying the odds, a healthy brittany made it to 37 weeks, a full-term pregnancy. They came in, whoa. You've got big babies in there. Reporter: Already, brittany's happily dropped 50 pounds in just a few days. And says the only one that's going to miss that gigantic baby bump is the family cat. For "good morning america," abbie boudreau, abc news, los angeles.

This transcript has been automatically generated and may not be 100% accurate.

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